Apparent motion display

A control circuit is described which drives recurrently alternating projection tachistoscope shutters or lights for the study of apparent motion. The device, easily constructed, provides reliable variation in temporal duration of stimuli and the interval between their presentation.     

The representation of depth in children's drawings of a table

Willats (1977) analysed developments in the drawing of a table in terms of the projection system in which the table top was represented, and concluded that representation of depth in drawing goes through a series of discrete stages, each of which can be identified with a projection system. A partial replication of Willats' study is presented here, using a much larger sample. The relationship between age and use of projection system found by Willats was in general supported. Not all the “stages” were found to be discrete, however, and an examination of the way in which the table tops were drawn shows that whilst the majority of older children appeared to use perspective, they did not use it correctly. A method is given by which tables that are drawn as if from a central viewpoint can be formally classified. It is concluded that development in the understanding of the representation of depth is not very closely linked to development in the use of projection systems.     

A purely temporal transparency mechanism in the visual system.

I report evidence for a purely temporal perceptual transparency mechanism. Rapid alternation of two images in the same location can result in the simultaneous experience of both, accompanied by a sense of transparency. This is true even when the sum of the two images does not appear transparent, which suggests that the percept is not mediated by the static transparency processes. At slow rates, alternating gratings were experienced as successive. As the rate was increased, by 8 Hz observers experienced the gratings as simultaneous. The rapidly alternating gratings are apparently processed separately before being combined for awareness by a process that integrates over about 120 ms. A final experiment tested whether the common presentation time of different parts of an image in alternation with another would cause the parts to perceptually bind. Observers did not distinguish between a rapidly alternating intact grating display and one in which halves of the display were exchanged in time. In other words, temporal binding across space did not occur. The temporal transparency phenomenon, in addition to informing theories of transparency and the dynamics of visual processing, may also be useful for the creation of transparent displays for electronic devices.     

Projection of a medium

Learning spaces, partial cubes, and preference orderings are just a few of the many structures that can be captured by a ‘medium,’ a set of transformations on a possibly infinite set of states, constrained by four strong axioms. In this paper, we introduce a method for summarizing an arbitrary medium by gathering its states into equivalence classes and treating each equivalence class as a state in a new structure. When the new structure is also a medium, it can be characterized as a projection of the original medium. We show that any subset of tokens from an arbitrary medium generates a projection, and that each state in the projection determines a submedium.     

Value Differentiation Between Enemies and Allies: Value Projection in National Images

The current study aimed to investigate value projection between Palestinians, Israelis, Americans, and Swiss as a function of their group's stance toward the Israeli‐Palestinian conflict. Drawing on image theory, we assumed that images—operationalized by value projection—would be a function not just of features of the target group, but of the rater group's relationship with the target group. Value projection can be seen as an indicator of (de)humanization as values represent goals and desirable behaviors of a person. We therefore expected higher projection to ally than to enemy groups, whereas we expected no difference in projection to out‐groups with neutral relations. Results show that allies did indeed project Security and Power to a higher degree to each other than to enemies, and enemies showed no, or even negative, projection onto each other. The ally of the enemy (Americans) was projected less negatively by Palestinians than vice versa, pointing to the higher complexity of third‐party images as opposed to the more classical ally and enemy images. As expected, Swiss students showed almost no difference in projection to the different out‐groups. These results confirm that the relationship between groups (e.g., alliance, enmity) rather than a consensual view of particular nations determines images.     

The effect of polar projection on the perception of euclidean structure from motion

The aim of the present study was to examine whether euclidean structure could be recovered from apparent motion sequences under polar projection. In Experiment 1, length judgments of two sides of a simulated triangle rotating in depth did not reveal effects of type of projection, polar or parallel, on the perception of euclidean structure. However, there was a significant correlation between simulated and produced slants. The results also indicated that absolute depth judgments could not be accounted for by a random mechanism suggested by Todd and Bressan (1990). Experiments 2 and 3, in which a continuous dot surface was substituted for the triangle, showed that polar projection information from a relatively large visual angle, 17.40°, as compared with a small visual angle, 4.35°, facilitated discrimination of depth. Produced height:width ratios were consistently related to simulated shape, although the depth dimension was underestimated. Finally, Experiment 4 showed significant correlations between simulated and produced height:width ratios that could be accounted for only by an analysis in whichX andY velocities were treated independently. As in previous experiments, the variation in the depth dimension was underestimated. It was concluded that the visual system utilizes the additional information that is available in polar projection when recovering structure from motion, but that for different reasons the perceived structure does not become euclidean. These reasons are discussed briefly.     

The relative contribution of contact and target lines in the magnitude of the Poggendorff effect

It is well known that a set of parallel lines can cause misperception of the projected path of an oblique. Most studies of this effect have emphasized either the proximal or the distal stimulus components--the line with which the oblique makes contact, or the line that serves as the target of the projection. An experiment is reported in which the relative contribution of the contact and target lines was examined. The results indicate that rotation of either line can determine the magnitude of the projection error.     

GENERALIZATION OF OBJECT NAMING AFTER TRAINING WITH PICTURE CARDS AND WITH OBJECTS

Generalization of four retarded children's object naming responses to stimuli in the natural environment was assessed after training with either objects or pictures of the objects. Generalization was typically greater after training with objects. In a second experiment, half of the stimuli that showed little generalization were retrained by alternating the original training object with an object that belonged to the same stimulus class as the training stimulus. The other half were simply retrained using the object. The alternating procedure resulted in substantial increases in generalization to untrained objects.     

Group-centrism in the absence of group norms: The role of need for closure in social projection

The need for closure (NFC) promotes group-centrism, referring to the pursuit of a shared reality in a group, commonly achieved through conformity to and introjection of group norms. The present study expands this perspective by examining how NFC motivates projection of one’s own norms on groups, as an alternative means to achieve epistemic security in the absence of clear group norms. In Study 1 (N?=?261), individual differences in NFC predicted social projection onto an incidental crowd, providing evidence for the generic effect of NFC on social projection. In line with the assertion that the epistemic value of a collectivity is a function of the degree to which the collectivity matters for the individual, Study 2 (N?=?239) and Study 3 (N?=?223) revealed that NFC effects on social projection were strengthened for in-groups and disappeared for out-groups. Furthermore, mediation analyses demonstrated that essentialist entitativity beliefs mediate the relationship between NFC and in-group projection.     

Error self-correction and spelling: improving the spelling accuracy of secondary students with disabilities in written expression

In order to improve the spelling performance of high school students with deficits in written expression, an error self-correction procedure was implemented. The participants were two tenth-grade students and one twelfth-grade student in a program for individuals with learning disabilities. Using an alternating treatments design, the effect of error self-correction was compared with a more traditional method of spelling practice. The intervention and follow-up phases were implemented over a 6-week period with maintenance checks conducted 4 and 8 weeks after the termination of instruction. Results indicated that the error self-correction procedure was superior to the traditional method of review during the intervention and follow-up phases, but some gains were lost during the maintenance phase.     

Retinal projection or size constancy as determinants of the horizontal-vertical illusion?

To compare the influence of the projected retinal size and of the figure size on the perception of the horizontal-vertical illusion, the target size, the viewing distance, and the slant of an illusion figure were varied. In the first experiment the illusion produced by two figures of the same object size but of different retinal size was compared with that of two figures projecting the same retinal size but differing in object size. The illusion diminished when the size of the retinal projection was increased, whereas a change in figure size did not change the illusion. In Exp. II the illusion figure was tilted backwards which reduced the retinal projection of the 'vertical' figure limb. The illusion decreased and became negative as a function of the retinal projection, but this decrease was relatively small compared with the reduction of the retinal image. The results are interpreted as supporting a retinal origin as an explanation of the illusion. Although there is strong evidence for size-constancy scaling in a tilted figure, constancy scaling is considered of minor importance as a determinant of the usual illusion.     

Anticipated cooperation vs. competition moderates interpersonal projection

Two experiments investigated the impact of anticipated interdependence on people’s projection of their characteristics onto an unknown target. After participants had rated themselves on a list of personality traits, they were led to expect a situation of cooperation or competition with another participant and rated this participant on the same list of traits. In both experiments, projection of self-attributed traits was stronger under cooperation than competition. This effect was independent of trait valence, whether defined a priori (Experiment 1) or as an idiosyncratic measure (Experiment 2). Experiment 2 also revealed that the moderation of interpersonal projection by interdependence was not driven by changes in participants’ self-representation. These findings suggest that the anticipated interdependence context influences the way we perceive similarity with unknown others. We discuss possible cognitive and motivational mechanisms underlying this effect.     

Gender differences and the Defense Mechanism Test: A comparative study of adolescents in psychiatric care and healthy controls

The aim of this paper was to study gender differences in the percept-genetic method Defense Mechanism Test (DMT) among a group of 60 adolescent subjects. Three subgroups were used: patients with psychotic disorders (Axis 1); borderline personality disorder (Axis 2) according to the DSM-IV classification system, and a non-patient group. The test protocols were scored with respect to 124 DMT variables and analyzed by means of the multivariate projection method Partial Least Squares (PLS) in latent structures. The overall results showed considerable gender differences in the whole group as well as in the subgroups. The most striking finding was that girls compared to boys were characterized by the perceptual defense identification with the opposite sex, which means that they perceived male gestalts instead of females in the stimulus picture. When both gender and diagnostic group membership were considered simultaneously, the influence of diagnostic group membership seemed to be stronger than gender even if there was an interaction between diagnoses and gender. It was concluded that gender must be considered when the DMT is used on adolescent populations.     

Efficient extrapolation of the view with a dynamic and predictive stimulus

In the real-world, the retinal projection of an object changes as we move, or as a moving object passes in front of us. We have to recognise objects, despite such retinal-projection changes. Many studies have shown that the time required to identify objects after a change in the retinal projection is longer than when there is no retinal-projection change. This recognition cost is referred to as the view-dependent effect. Previous researchers have studied the view-dependent effect while disregarding the predictability of retinal-projection changes. Here, we demonstrate that there is no view-dependent effect when the predictability is introduced, in the case where participants track moving objects by head-turning or eye-movement in a virtual environment. Violation of the predictability, such as an unpredictable retinal-projection change or a movement of the first stimulus that was inconsistent with a subsequent retinal-projection change, caused a view-dependent effect. Moreover, we found that extraretinal information such as head-turning or eye-movement was unnecessary for view-independent recognition. These results indicate that humans can extrapolate to the tested view from the studied view in a view-independent way when retinal-projection change is predictable from the visual stimulus.     

Anger and the Use of Defense Mechanisms in College Students

ABSTRACT It was hypothesized that experimentally induced anger would result in an increased use of defense mechanisms in college students. As predicted from the theory of defense mechanism development, the Thematic Apperception Test (TAT) stories of angered students showed a higher level of use of projection and identification, and the use of these defenses was significantly correlated with the presence of aggressive content in the stories. The results were consistent with previous studies in showing that the predominant defenses of late adolescents are projection and identification, and that men use more projection than women.     

Perceptual grouping in audition

The present experiments evaluated the effect of relative frequency as a determinant of the figure-ground organization of sequences of auditory tones. Observers counted sequences of 20 ms tones that were presented at the same frequency or that alternated between two different frequencies. The alternating tones differed in frequency by one whole tone, seven tones, or nineteen tones. Counting accuracy increased with increases in the silent interval between the tones. When the alternating tones differed by seven or nineteen tones, counting was disrupted at rates of presentation of eight tones per second or slower. In contrast to this decrement in the counting of tones that alternated by over an octave, very little decrement was observed when the tones alternated by just one whole tone. The best subjects counted these alternating tones more accurately than the tones presented at the same frequency. The poorest subjects showed a small decrement even when the tones alternated by just one whole tone. The results were discussed in terms of determinants of figure-ground organization in auditory information processing.     

APPLICATIONS OF A SEQUENTIAL ALTERNATING TREATMENTS DESIGN

We propose the use of a combined version of the alternating treatments and multiple baseline designs in situations in which a traditional baseline (no treatment) condition either does not provide an adequate contrast condition or is not feasible or practical due to clinical constraints. We refer to this design as a sequential alternating treatments design because two treatments are initially implemented in a random or counterbalanced fashion and are followed by a sequential change in one or both treatments across settings, subjects, or tasks. The effects of the independent variables are assessed first by analyzing the two series of data points representing the different treatments (relative effects) and then by assessing changes in one or both series, as application of the alternative treatment is introduced sequentially. The sequential application of treatment provides an analysis of control in the same manner as the multiple baseline design; the initial alternating treatments phase provides a contrast condition in much the same manner as a baseline condition. Applications of this design to the assessment of peer training and self-injurious behavior are described.     

RAP: A computer program for exploring similarities in behavior sequences using random projections

A computer program (RAP, for random projection) for exploring similarities between and within sequences of behavior is presented. Given a time window of a sequence, the program calculates a signature, a real-valued vector that is a random projection of the contents of the window (i.e., the codes occurring within it and their relative location, or onset and offset times) into an arbitrary K-dimensional space. Then, given two different time windows from the same sequence or from different sequences, their similarity is computed as an inverse function of the Euclidean distance between their respective signatures. By defining moving (overlapped or not overlapped) windows along each sequence and calculating similarities between every pair of windows from the two sequences, a map of similarities or possible recurrent patterns is obtained; the RAP program represents them as gray-level lattices, which are displayed as mouse-sensitive images in an HTML file. Computation of similarities is based on the random projection method, as presented by Mannila and Seppänen (2001), for the analysis of sequences of events. The program reads sequence data files in Sequential Data Interchange Standard (SDIS) format (Bakeman &; Quera, 1992, 1995a).     

Correcting the oral reading errors of a beginning reader

Correcting student errors is an important educational concern for teachers. In this study, an alternating treatments design was used to compare the effectiveness of four methods for correcting oral reading errors, including immediate word supply, delayed word supply, sound out (phonics analysis), and directed rehearsal techniques. The subject was a 6-year-old beginning reader with average ability. Results showed that the directed rehearsal procedure was the most effective method. This study demonstrated that teachers can use rigorous research methods in their own classrooms to determine which teaching strategies they should use with their students.